pear leaf disease

Asked July 8, 2020, 8:12 PM EDT

My dwarf moonglow pear has this leaf disease. Leaves turning brown. See photos. This is occurring on older branches and not on new growth.
To me, it doesn't look like the photos I found online of fireblight, scab or fabraea.

I have 2 standard Bartlett pear trees within 25 feet and they have no sign of this.

Oakland County Michigan

3 Responses

Hello,

Pyrus communis ‘Moonglow’ is listed as highly resistant to fire blight. Pears do want moist well drained soil so I’m wondering how much water during the drought your pear is getting. In some pictures I do see a couple spots of rust on the leaves, but rust doesn’t brown the leaves. Here are a couple possibilities-

Spider mite damage is most likely to become a problem during hot, dry conditions in July to September when mites reproduce rapidly. Look for “burning” or russetting of leaves. Test for small mites on undersides of leaves by shaking a branch over a white paper and checking for small moving specks, or use a magnifying hand lens to examine undersides of leaves. Only treat if “leaf burn” is evident. Wash tree down with stiff spray of water or apply insecticidal soap according to label directions.

Predator mites commonly suppress spider mites, so avoid insecticides unless damage is severe and control wasn't achieved with water spray.

http://www.virginiafruit.ento.vt.edu/ermpear.html

This could also be the result of chemical herbicide drift onto the tree when something else was being sprayed nearby, such as weed killer on lawns. This may happen when winds are over 5 miles per hour or gusting during the time spraying was done. Non- garden chemical vapors , such as driveway sealant, sometimes affect plants.

https://images.bugwood.org/series.cfm?coll=72289&color=transparent

If none of these seems likely, please submit your pictures and question to MSU Plant and Pest Diagnostic lab. During Covid19 they request you start by emailing them pictures and plant care history to pestid@msu.edu

If they need samples they will contact you. Here is their website-https://www.canr.msu.edu/pestid/

No evidence of spider mites or other insects. Several of the driest leaves fell off when I shook the branches.
I don't believe it was a chemical herbicide. I have only sprayed 'fruit tree spray' this year.
I think it is possibly due to dry weather. We had 10 or more consecutive sunny days of 90+ degrees. I watered this tree once in that time. The other trees seemed to handle it fine but maybe this tree does not have a sufficient root system yet.

I agree, especially if the tree has been transplanted within the last 3-4 years. It can take some time to recover from drought stress, so you may see some more leaves drop after watering it.